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F  O R A M I N I F E R S (FO R A M ) I  N D E X

D6

What

What Is It?

BENCHMARK

Foraminifers (forams) are microscopic, shelled

FI > 4: Physical environment suitable

FI

protists (one-celled organisms with a nucleus and

for reef growth with potential for

other internal structures) belonging to a variety of

recovery.

species that inhabit a wide range of environmental

TA R G E T

conditions.

FI > 6: Physical environment conducive

The FORAM Index (Foraminifers in Reef Assessment

for reef growth and recovery.

for

and Monitoring: FI) evaluates water quality (primarily

nutrient loads). The index value is calculated according

RED FL AG

to the relative abundances of different benthic foram

functional groups found in surface sediments of reef-

2 < FI > 4: Physical environment

associated environments.

marginal for reef growth and unsuitable

for

for recovery.

FI

FI < 2: Physical environment unsuitable

for reef growth.

for

Populations of larger foraminifers are immune to coral-

specific diseases, and they recover more quickly from

physical impacts than do long-lived coral populations.

They may also be less sensitive to the effects of

overfishing because they have less direct contact

and fewer competitive interactions with macroalgae

for reef substrate. Thus, they are less responsive

to changes in herbivory levels and can be used to

discriminate between the influence of water quality

factors (like nutrient concentrations) and ecological

controls (like herbivory levels) with regard to declines

in reef quality.

The utility of the FORAM Index has been well

established based on formal U.S. Environmental

Protection Agency (EPA) evaluation guidelines for

Pamela Hallock

Why Do We Measure It?

ecological indicators.

Foraminifers with algal symbionts have similar water

How Do We Measure It?

quality requirements to reef-building, zooxanthellate

First, samples of seafloor sediment from reef-

corals. Since coral reef communities are sensitive to a

associated environments are collected using small

variety of stresses, it is critical to have an indicator of

plastic jars or film canisters13. Next, in a laboratory,

water quality conditions that can be measured even

the foraminifers are separated from the sediment

in the absence of healthy coral populations following

samples and identified according to functional group:

mass mortality events (e.g., disease outbreaks

· Symbiont-bearing,

or severe bleaching). Foraminifers can indicate

· Stress-tolerant, or

whether water quality conditions (particularly nutrient

· Small, heterotrophic.

concentrations) will likely support coral recovery from

disturbances or not.

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